A Protocol to Reduce Interobserver Variability in the Computed Tomography Measurement of Orbital Floor Fractures

Abstract

Orbital fracture detection and size determination from computed tomography (CT) scans affect the decision to operate, the type of surgical implant used, and postoperative outcomes. However, the lack of standardization of radiological signs often leads to the false-positive detection of orbital fractures, while nonstandardized landmarks lead to inaccurate defect measurements. We aim to design a novel protocol for CT measurement of orbital floor fractures and evaluate the interobserver variability on CT scan images. Qualitative aspects of this protocol include identifying direct and indirect signs of orbital fractures on CT scan images. Quantitative aspects of this protocol include measuring the surface area of pure orbital floor fractures using computer software. In this study, 15 independent observers without clinical experience in orbital fracture detection and measurement measured the orbital floor fractures of three randomly selected patients following the protocol. The time required for each measurement was recorded. The intraclass correlation coefficient of the surface area measurements is 0.999 (0.997-1.000) with p-value < 0.001. This suggests that any observer measuring the surface area will obtain a similar estimation of the fractured surface area. The maximum error limit was 0.901 cm(2) which is less than the margin of error of 1 cm(2) in mesh trimming for orbital reconstruction. The average duration required for each measurement was 3 minutes 19 seconds (ranging from 1 minute 35 seconds to 5 minutes). Measurements performed with our novel protocol resulted in minimal interobserver variability. This protocol is effective and generated reproducible results, is easy to teach and utilize, and its findings can be interpreted easily.

Computer-Aided Fracture Size Measurement in Orbital Fractures—An Alternative to Manual Evaluation

“…To overcome problems of manual estimations, various software have been proposed. Compared with previous studies done using computational analysis for calculating fracture area, 1,15,20,21 our results show a similar variability. However, most of the aforementioned analysis methods require on the user pointing to several margin points along the fracture margins and are thus somewhat laborious.…”

Predictors of enophthalmos among adult patients with pure orbital blowout fractures

“…Measurement of the fracture size was performed based from Ang et al (2015) [ 25 ]. The measurement started at the coronal view of the scan.…”

Integration of rotational angiography enables better dose planning in Gamma Knife radiosurgery for brain arteriovenous malformations

“…retrospectively created two treatment plans (one before and one after RA integration) for each patient. Aiming for a standardized planning method to reduce inter-and intraobserver variabilities, 1,39,41 we used the following protocols during dose planning; 1) the radiosurgical target should be determined by meticulously comparing images acquired using a variety of imaging studies; 2) each shot should be placed inside the radiosurgical target; 3) if possible, feeders and drainers should be excluded from the radiosurgical target; 4) if it is difficult to judge whether a vessel belongs to a nidus, feeder, or drainer, trace the vessel both downstream and upstream and determine where it belongs; 5) radiosurgical doses should be prescribed with a 50% ± 5% isodose line; and 6) the gamma angle should be fixed at 90°.…”

“…Although we could not fully incorporate these variabilities, we did at least partially address them by using the standardized contouring protocol and allowing the physicians to use multimodal imaging. 1,39,41 FIG. 3.…”